Akademik Veri Yönetim Sistemi
JOURNAL OF THE FACULTY OF ENGINEERING AND ARCHITECTURE OF GAZI UNIVERSITY, cilt.25, sa.4, ss.693-699, 2010 (SCI-Expanded)
Polymer electrolyte membrane fuel cells (PEMFC) are considered to be the promising alternative energy source for vehicles and other portable applications due to their high efficiency, confidence and being an environmentally friendly technology. The most important part of PEMFC is polymer electrolyte membrane that serves as carrier for the transportation of protons from anode to cathode and acts as a barrier to avoid the contact between the fuel and oxidant. The perfluorosulfonic acid polymer membranes such as Nafion (R), are used as the electrolytes in PEMFC because of their favorable chemical features and high proton conductivity. However, because of loss of proton conductivity of Nafion (R) membranes at high temperatures and their high cost causes to large number of studies have been devoted to develop alternative membrane materials. The aim of this study is to develop poly(vinyl alcohol) (PVA) based composite membranes for fuel cells that has better properties and cheaper than the Nafion (R) membrane. PVA based membranes with different molar ratios were prepared to understand the effect of their hypophosphorous acid (H3PO2) and tetraethyl orthosilicate (TEOS) contents on the conductivity of the membranes. Membranes were characterized by Fourier transform infrared spectroscopy (FT-IR), water uptake capacity, swelling ratios, ion exchange capacity and conductivity measurements. Water uptake percentages of membranes without swelling were found as changing in the range of %20-140 depending on their doped material content. Ion exchange capacities of membranes change in the range of 1.35 - 2.86 meq/g and their proton conductivities at room temperature and 100% RH take place in the range of 0.56 - 3.43 mS/cm. These membranes which were developed in this study for fuel cells, are promising alternative for expensive commercial perflorunated membranes.